1. Field of the Invention
The present invention relates to a stereoscopic video reproduction device, a stereoscopic video reproduction program and a non-transitory computer-readable recording medium therefor, a stereoscopic display device, a stereoscopic imaging device and a stereoscopic video reproduction method. Especially, the present invention relates to a technique of reproducing a stereoscopic video of a stereoscopic video file in which a stereoscopic image formed with a plurality of viewpoint images is consecutively recorded in a time axis direction.
2. Description of the Related Art
A stereoscopic imaging device takes images of an object in right and left viewpoints using two right and left imaging units arranged with parallax, acquires the viewpoint image for the left eye and the viewpoint image for the right eye respectively and records them in a recording medium. When these acquired right and left viewpoint images are read from the recording medium, input in a 3D display that can perform three-dimensional (3D) display, and are displayed such that the viewpoint image for the left eye and the viewpoint image for the right eye can be visually checked by right and left eyes respectively, it is possible to recognize the result as a stereoscopic video.
By the way, the parallax amount between the recorded right and left viewpoint images varies depending on the change in an imaging scene, the movement of the object, the change in the zoom magnification or the like, and, meanwhile, the 3D display has various screen sizes. Therefore, in a case where reproduction display of a stereoscopic video is to be performed, there is a case where the parallax amount for the stereoscopic video is not suitable for the size of the 3D display. In such a case, there arises a problem that the pop-up amount and pop-down amount from the screen are excessive and it is not possible to recognize the stereoscopic video as a natural stereoscopic video.
Japanese Patent Application Laid-Open No. 2004-180069 discloses a technique of: acquiring suitable screen size information related to the screen size suitable for reproduction of a stereoscopic image, display screen size information of a 3D display, suitable visual distance information related to the suitable distance to a display screen for an observer to view the display screen at the time of reproduction, and visual distance information related to the distance from the observer to the display screen of the 3D display, in addition to image information that can be stereoscopically viewed; setting the shift amount (offset) between the left eye image and the right eye image based on these items of information; and adjusting the stereoscopic feeling of the displayed image.
It is not clear whether the stereoscopic image disclosed in Japanese Patent Application Laid-Open No. 2004-180069 is a still image or a video. In the case of a stereoscopic video, the parallax amount of right and left viewpoint images varies depending on the change in an imaging scene, the movement of an object, the change in the zoom magnification, and so on. Even if, for the sake of argument, the parallax amount of a stereoscopic video is adjusted by the technique disclosed in Japanese Patent Application Laid-Open No. 2004-180069 such that the stereoscopic video has a natural pop-up amount, it is considered to adjust the parallax amount in units of frames of the stereoscopic video. However, in this case, there is a problem that a feature as the stereoscopic video in which the stereoscopic feeling varies is lost and an unnatural stereoscopic video is provided.
By the way, on a display screen of a 3D display, in a case where the right eye image has a parallax in the right direction with respect to the left eye image, a stereoscopic image is visually checked as an image with a larger depth than the display screen, but, when the screen size of the 3D display increases, this parallax increases too. When the parallax exceeds a man's binocular interval, binocular fusion is impossible (i.e. binocular vision is impossible).
Although Japanese Patent Application Laid-Open No. 2004-180069 discloses acquiring a stereoscopic image in which the optimal stereoscopic degree (i.e. depth amount) is adjusted in proportion to the display screen size of the 3D display, it does not disclose adjusting the shift amount between the left eye image and the right eye image such that the above-mentioned binocular fusion is not impossible. Further, since it does not contain description related to the maximum parallax amount of the distant view side (or depth side) of a stereoscopic image either, the stereoscopic image display device disclosed in Japanese Patent Application Laid-Open No. 2004-180069 cannot adjust the shift amount between the left eye image and the right eye image such that the parallax does not exceed the man's binocular interval regardless of the screen size of the 3D display.